It has become common that vehicles, such as motor vehicles, are provided with airbag devices that inflate and deploy airbags in the vehicles to absorb impact applied on occupants in an emergency, such as a collision or a sudden deceleration. Typically, these airbag devices include an airbag that is normally folded and is inflated and deployed in an emergency, an inflator that supplies gas to the airbag, a retainer that retains the airbag and the inflator, and an airbag cover that covers the airbag.
In a collision or a sudden deceleration of a vehicle, the inflator supplies gas to the airbag to inflate the airbag, causing the airbag cover to tear. Then, the airbag is released in the vehicle and inflated and deployed. In particular, in the case of passenger airbag devices, an airbag is inflated and deployed in a space surrounded by an instrument panel, a windshield (front glass), and an occupant.
For example, airbag devices in which rectification means, such as inner bags or diffusers, is disposed in the airbags have been proposed, as disclosed in Japanese Laid-open Patent Publication Nos. 10-203280 and 2001-233152.
The rectification means disclosed in Japanese Laid-open Patent Publication No. 10-203280 includes an inner bag that is held sandwiched between a windshield (front glass) and an instrument panel. A discharging hole is provided in the inner bag to facilitate vertical deployment of the airbag. Thus, in the airbag device disclosed in Japanese Laid-open Patent Publication No. 10-203280, the inner bag can be fixed between the windshield (front glass) and the instrument panel because of the internal pressure of the inner bag, whereby the flow of gas supplied from the discharging hole can be stabilized to achieve a stable deployment behavior of the airbag.
The rectification means disclosed in Japanese Laid-open Patent Publication No. 2001-233152 includes an inner bag formed in the shape of a small bag that project to the rear of the vehicle within the rear end of the instrument panel. An upper hole and a lower hole are provided in the inner bag. The upper hole is provided at a portion protruding to the rear of the vehicle beyond the terminal end of a split door, and the lower hole is provided at a portion protruding beyond an opening in the instrument panel. Thus, the airbag device disclosed in Japanese Laid-open Patent Publication No. 2001-233152 can reduce the possibility of the inflated inner bag contacting with an occupant approaching the instrument panel, whereby the upper and lower holes are not blocked, and the airbag can be inflated and deployed preferentially in the vertical direction.